Ion‐“distillation” for isolating lithium from lake brine

Lithium demands increase dramatically and make it highly attractive to develop advanced ion separation technology/material. However, high Mg2+/Li+ ratio impedes the extraction due to the difficulties in separation of the two ions. Here, we propose an ion-“distillation” technology based on electro-membrane stacking for the extraction of Li+ from lake brine (Mg2+/Li+ ratio: 31.58). This technology employs commercially available monovalent ion-selective membranes, and ions are driven by electric. Using the four-stage ion-“distillation” technology, selectivity values of 26,177 and 27,000 are achieved between Li+ and Mg2+ and between Cl− and SO42−, respectively. The electro-stripping mechanism when monovalent ion migrating across the membranes probably magnitude the Li+ selectivity, which is higher than the other reported values in the literature for membrane processes, and the purity of the final LiCl product is greater than battery grade (99.95%). The proposed process can potentially be applied in efficient ion fractionation and special separations.